Influence of the trunk position on knee kinematics during the single-leg landing: implications for injury prevention

ABSTRACT

The purpose of the present study was to investigate the influence of the trunk position during the single-leg landing on the knee angle and muscle activity. Forty healthy university students (20 men and 20 women) performed right single-leg landings from a 40 cm-high platform with the trunk in neutral, flexion, extension, and right and left lateral flexion. Knee flexion and valgus angles were determined by two-dimensional video analysis, and rectus femoris (RF) and biceps femoris (BF) muscle activities were assessed. The knee flexion angle was significantly higher in the trunk-flexion position than in the other trunk positions. The knee valgus angle was significantly lower in the trunk-neutral and trunk-flexion positions than in the trunk-extension, trunk-right-lateral-flexion, and trunk-left-lateral flexion positions. Muscle activity of the RF was significantly lower in the trunk-flexion position than in the trunk-extension position and that of the BF was significantly higher in the trunk-flexion position than in the trunk-neutral, trunk-extension, and trunk-right-lateral-flexion positions. Single (right)-leg landing with the trunk in flexion may confer a low risk of anterior cruciate ligament injury compared to that with the trunk in extension or right lateral flexion.

KEYWORDS:

• Anterior cruciate ligament
• knee angle
• quadriceps femoris
• hamstrings

Acknowledgments

We thank Mr. Kazuki Okura and Mr. Manabu Kai for their valuable contributions toward participant recruitment and data collection for this project.

Disclosure statement

No potential conflict of interest was reported by the authors.